Experiment-8: “Determination of the specific heat of metal”
Object : To find the specific heat of a 3 kind of metal.
Theory : When energy is added to a substance and no work is done,
the temperature of the substance usually rises. (An exception to this
statement is the case in which a substance undergoes a change of
state—also called a phase transition—) The quantity of energy
required to raise the temperature of a given mass of a substance by
some amount varies from one substance to another.
For example, the quantity of energy required to raise the
temperature of 1 kg of water by 1°C is 4 186 J, but the quantity of
energy required to raise the temperature of 1 kg of copper by 1°C is
only 387 J. In the discussion that follows, we shall use heat as our
example of energy transfer, but we shall keep in mind that we
could change the temperature of our system by doing work on it.
The heat capacity C of a particular sample of a substance is defined
as the amount of energy needed to raise the temperature of that
sample by 1°C. From this definition, we see that if heat Q produces a
change ∆T in the temperature of a substance, then
□ = □. ∆□ eq. 1.0
The specific heat c of a substance is the heat capacity per unit mass.
Thus, if energy Q transferred by heat to mass m of a substance
changes the temperature of the sample by ∆T, then the specific heat
of the substance is
Specific heat is essentially a measure of how thermally insensitive a
substance is to the addition of energy. The greater a material’s
specific heat, the more energy must be added to a given mass of the
material to cause a particular temperature change.
From this definition, we can express the energy Q transferred by heat
between a sample of mass m of a material and its surroundings for a
temperature change ∆T as
□ = □. □. ∆□ eq 1.2